Photochemical ozone production in tropical squall line convection during NASA Global Tropospheric Experiment/Amazon Boundary Layer Experiment 2A

Transient effects within the cloud are examined with a combination of two-dimensional cloud and one-dimensional photochemical modeling. Tracer analyses using the cloud model wind fields yield a series of cross sections of NO_x, CO, and O₃ distribution during the lifetime of the cloud; these fields are used in the photochemical model to compute the net rate of O₃ production. Analysis of cloud inflows and outflows is used to differentiate between air that is undisturbed and air that has been modified by the storm. These profiles are used in the photochemical model to examine the aftereffects of convective redistribution in the 24-hour period following the storm. Total tropospheric column O₃ production changed little due to convection because so little NO_x was available in the lower troposphere. However, the integrated O₃ production potential in the 5- to 13-km layer changed from net destruction to net production as a result of the convection. -from Authors